A meshless numerical library C++ Medusa is claimed to be dimension indenpendent. The implementation itself strongly depends on the C++ templates.
For example in this paper they use Medusa to sole a Poisson problem in 1, 2, 3, and 4 dimensional space, with basically the same code.
I'd recommend SCIP or HiGHS (www.highs.dev). On the industry standard benchmarks (http://plato.asu.edu/bench.html) their relative performance is similar, but on specific classes of MIPs one may be very much better. The performance of HiGHS on MIPs is improving rapidly, so will probably overtake SCIP meaningfully in 2022